This experiment involves recording of the electroencephalographic activity of the brain (EEG dynamics) and event related potentials (ERP) during the performance of a visual-orientation perception and visuo-motor tracking task that humans and astronauts may encounter on a daily basis. Within the experiment, five cognitive processes (Perception, Attention, Memorization, Decision and Action) were studied. The stimulus set also contained task-irrelevant novel visual stimuli to allow assessment of electrophysiological correlates of novelty processing. Psychophysical analyses were measured during these tasks. EEG and ERP recordings were also collected to allow the evaluation of the arousal levels of the subjects. In addition to conventional spectral analysis, EEG were quantified with maps of linear and nonlinear complexity. As the novel conditions of microgravity accompanied by a multitude of stressors may place an increased load on the cognitive capacity of the human brain, it was hypothesized that sensory signals and motor responses must be processed and interpreted in a new reference frame.
Each data collection session was organized into different tasks. The first task assessed Visual Orientation Perception, during which the crewmember compared images and provided feedback if they were identical or not. The Visuomotor Tracking task displayed a moving target on the screen and the crewmember was asked to track the target. The EEG control task displayed a checkerboard pattern, and the EEG signals were measured with eyes open and closed. Two other control tasks involved following a visual target with the eyes in order to calibrate the electrooculogram (EOG) recordings. During Baseline Data Collection (BDC), all tasks were performed while the subject was sitting comfortably in a chair. Preflight BDC was requested for L-90, L-60 and L-30. Postflight BDC sessions were planned for R+2/3, and a second session within the first 10 days postflight. A magnetic resonance image (MRI) scan of the brain was also requested at the pre- and postflight sessions.
The same tasks were performed during in-flight operations as they were planned during BDC. During all tasks the subject was lightly restrained with belts, approximating as much as possible a free-floating condition, but restraining the subject to a limited volume with the International Space Station (ISS) module.
It was observed that the power of the spontaneous 10-Hz oscillation recorded in the eyes-closed state in the parieto-occipital and sensorimotor areas increased in the absence of gravity. The suppression coefficient during the arrest reaction and the related spectral perturbations produced by eye-opening/closure state transition also increased on orbit. These results in terms of current theories on the source and the importance of the alpha rhythm for cognitive function are discussed in the publication cited below.